Attempts have been widely made to apply so-called tapes comprising a nonsteroidal antiphlogistic (or anti-inflammatory) analgesic drug contained in an oily pressure-sensitive adhesive to therapeutic uses. For example, Japanese Patent Laid-Open Gazette No. 227819/1984 has disclosed an attempt to administer a nonsteroidal antiphlogistic analgesic drug which is contained in an acrylic pressure-sensitive adhesive located on a composite backing consisting of a nonwoven fabric and a film. Further, Japanese Patent Laid-Open Gazette No. 139615/1985 has disclosed an attempt to administer ketoprofen which is contained in a pressure-sensitive adhesive comprising polyisobutylene/paraffin/rosin-modified glycerol ester, to allow the ketoprofen to be percutaneously absorbed. Japanese Patent Laid-Open Gazette No. 227524/1988 has disclosed an attempt to administer flurbiprofen together with an oily base. Furthermore, Japanese Patent Laid-Open No. 40420/1989 has disclosed an attempt to administer, together with an oily base, a nonsteroidal antiphlogistic analgesic drug having a carboxyl group.
However, none of these attempts are satisfactory in drug-release characteristics or percutaneous absorption characteristics. It is therefore urgently required to develop a preparation having superior properties.
It is an object of the present invention to provide an antiphlogistic analgesic plaster having characteristics remarkably improved in the following points:
(1) improvement in percutaneous absorption (improvements in the solubility and releasability of a nonsteroidal antiphlogistic analgesic drug in a base), PA1 (2) improvement in drug-releasability (selection of a backing not adsorbing a nonsteroidal antiphlogistic analgesic drug), PA1 (3) relief from side effects including skin rash caused by repeated plastering (utilization of a safe base and search for not adhesion but stickiness through the establishment of an appropriate compositional ratio of the base), and PA1 (4) convenient usability in the remedial field (impartment of such stretchability as to enable the stickiness to a flexional part). PA1 (a) at least one nonsteroidal antiphlogistic analgesic drug selected from among ketoprofen, flurbiprofen, loxoprofen, ketorolac and ester derivatives or salts thereof; PA1 (b) a solubilizer comprising a combination of a rosin ester derivative with l-menthol; PA1 (c) a styrene/isoprene/styrene block copolymer employed as a base polymer; PA1 (d) a softener; and PA1 (e) a backing comprising a polyester cloth. PA1 (1) improved percutaneous absorptivity, PA1 (2) improved drug-releasability, PA1 (3) reduction in side effects including skin rash caused by repeated plastering, and PA1 (4) convenient use in the field of remedy (impartment of such a stretchability as to enable the plaster to stick to a flexional part).